If a woman is ovulating at the time of sex, sperm will be ejaculated into the vagina and will reach the fallopian tubes within a few minutes to half an hour, where it will unite with the egg and develop into a fertilized egg, leading to pregnancy. As long as the egg and sperm are able to unite and develop into a fertilized egg, the woman will become pregnant. If a woman’s ovaries do not ovulate and she is in a safe period, the egg and sperm will not unite and will not lead to pregnancy. If a woman does not want to get pregnant after having sex, it is best to use emergency contraceptives or penis condoms.